Broke Back Willow Tree
by RenaRoo
Summary: They are kindred spirits, daughters thrown to the wolves. Sin thought she was alone, but that's why Cassandra took her in. They're alone together. They're sisters.


ladyloveandjustice prompted: okay prompt…i don't know if you've already done this or not, but Cass mentoring Sin? I remember you mentioning the idea a while back! Sorry if you've already done it!

As much as I have wanted to and been meaning to, I have not actually gotten to this yet! And I'm completely excited to have this prompt! Thank you so much! I hope I manage to do it justice!

Batman, Birds of Prey and related properties © DC Comics  
story © RenaRoo

 **Broke Back Willow Tree**

Canary is… _unhappy_ with the settlement.

At first it seemed like such a given to all involved: Cassandra is, after all, possibly the only person on the planet who is trained to handle Sin's unique abilities. She is the only one who is capable of surpassing Shiva, as Dinah's last encounter unfortunately bore testament to. And - more than any of that - she is the very one to have brought up the mentorship.

But a six month road trip (cut down only by Batman's suggestion, seemingly unhappy with the prospect of losing his own daughter for a year to this endeavor) with only Cassandra Cain and Sin Lance seems a bit much.

Cassandra is nothing if not insistent, however. And it's as their bike crosses the Gotham City limits that Sin's bravado from the departure with her adopted mother fades completely.

They were only _just_ reunited. Cass understands what it feels like to lose one's family so soon after finding it again.

She squeezes Sin's shoulder but does not stop. They have a long drive. And this is a hard lesson to learn.

* * *

Eating burgers at a truck stop is surprisingly relieving. The motel across the street is paying for their meals after they initially rejected Cassandra's attempt to pay for the room with Bruce's card. One call to Tim had given them the room free, a full tank of gas, and their meal of choice.

Sin likes burgers. Cass does, too.

"You must be sisters," the waitress says as she serves them their milkshakes.

At first, Sin opens her mouth to reply, but she nervously darts her eyes to Cassandra.

Cass takes another bite from her burger. "No," she answers between chews. "Better."

The waitress looks between them before feigning a smile and leaving the table. If her hackles are raised, Cass cannot say she feels too sorry. It is wrong to make assumptions, and Cass and Sin are not even of the same race.

Sin's bright eyes are on Cassandra as she tucks a piece of hair behind her ear. "Sister, she says it's best to be like a willow tree. To bend to the winds. Or else break."

"Hmm," Cass returns, reaching for the ketchup. Sin offers it to her. "Winds have to be very strong to knock over a tree. Even if it stands tall."

She dumps the ketchup onto the plate and then offers it back to Sin who repeats her action almost exactly. Cass feels a fond smile on her lips.

The younger girl chews on her cheek as she mulls over Cass' reply. She then looks up, cheeks flushed. "Did… did you mean it? When you said we are _better_ than sisters?"

Cass smirks and offers the girl her fry, remembers the exact words Barbara used. "We are… _kindred souls._ We match."

While Sin ducks her head to hide it, Cassandra can see the way the girl's eyes water.

It makes Cass hurt in her chest.

* * *

Star City is a long way from Gotham, but they reach it. Together. And there hasn't been a word said to either of their families, as per the agreement.

Sin cries when they reach the harbor. Cass stands by her.

"They said I died," she sobs, unmoving. Standing strong. "Here. Right… out there."

Cass looks out to the cold water. She feels her overcoat smack at the breeze.

"I didn't really die," she whispers. "But I might… it's the _same_ as dying. When… when your family does… doesn't really care."

Looking to the horizon, Cass remains silent. Her face stings at the trail of her tears, and her chest is clenched in ways that almost feel dangerous.

She knows this feeling very well.

"Do you know?" Cass asks as she steps behind Sin, opens her coat up enough to then pull the younger girl inside it. They're wrapped together in the coat's warmth as the wind licks at them and attempts to steal their voices. "Why? Do you know _why?"_

"Danger," Sin answers as Cass kneels, better wrapping her up in the coat. Her tiny arms still quiver. "The League… I was in danger."

Cass stares into her eyes, frowning. Sad. "You're lying."

The little girl's face crumples and she lets out a loud bark of a cry. "I'm _dangerous._ I _know_. I _know_ how to… to do bad things. I'm _good_ at doing them. Sister will never keep me. She has to send me away. Because I know bad. How do I _stop_ knowing how to hurt?"

Without a moment's hesitation, Cassandra pulls the girl into her arms and begins to rock her, letting her cry more and louder.

She waits a moment longer before taking a shuddering breath of her own.

"You never stop knowing," she at last replies.

Sin cries harder.

* * *

At first, Sin is reluctant. She has never sparred since coming into Dinah's care.

Cass is changing that.

"I can _hurt,"_ Sin reminds Cass emphatically, even as she instinctively gets into a beautiful silat. Her body is tense with excitement… and concern. She's ashamed for how much she's enjoying this idea.

So Cass grins like a feral cat and waves her on. "Not _me,_ you can't."

The initial moves have to be Cass', as Sin remains conflicted and coiled. Which is something Cass accepts even as it becomes increasingly apparent that the girl has no true conflict for which moves she attempts to do.

When Cass' challenge finally catches up with Sin, things become interesting and Cass has to actually put some effort into her reflexes.

They fight like a choreographed ballet, and it fulfills something in Cass she wasn't really aware she had needed.

Until she catches the Talon Strike aimed for her jugular, and sees the breathless excitement on Sin's face. The girl does not use the lethal strike with any more or less reservation than the sparring techniques they had been using.

"This move is dangerous," Cass says carefully, her face as neutral as possible. She imagines her full faced cowl - the one cut up and refurbished after left in her best friend's care - is protecting her features from the concern behind her words. "Have you used it since coming to America?"

Sin swallows hard. She looks nervous. "Am I in trouble? Should I not do this anymore?"

"No," Cass says softly, slowly returning Sin's hand to her. "We will now do this every day. Twice when we are on the road. Three times when we're stopped. You will show me _every move_ you know. And I will teach you how to use them better."

That makes the younger girl's eyes widen. "But… _that could hurt people."_

"It's a part of you," Cass says confidently. "It is powerful. But knowing how to use it. How to _not_ use it the way you were taught. That. That is the greatest power of all."

Slowly, understanding dawns on Sin right before Cass' eyes. "You _know,"_ she whispers. "How to _hurt."_

Cass nods carefully. "But. Now. I know _better."_

* * *

She emerges from the shower, hair still sopping wet, and looks to Sin on the other bed, watching cartoons. The girl became fairly accepting of Cass' preference for no pajamas a month ago.

"My hair is too long," Cassandra announces as she digs through her night bag. "Don't like it."

The scissors are in the pocket.

Curious, Sin scoots to the edge of her bed and cocks her head to the side. "You're cutting your own hair?" she asks, amused.

"Nope," Cass replies before crossing the room and plopping onto the ground beside Sin's bed. She hands the scissors back. "You can."

Sin's breath hitches.

"Scissors can hurt," Sin reminds her carefully.

"Yes," Cassandra responds, turning enough to look into Sin's eyes. _"Anyone_ can hurt with scissors. But you do not _want_ to hurt me. You will _try_ not to hurt me. And so. You won't."

Slowly, Sin begins to grasp onto the lesson.

"I can do this," Sin musters.

"You _can,"_ Cass assures her.

Sin begins snipping.

* * *

The two most dangerous women in the world decide one night to forego the motel experience and instead set sleeping bags up on the grassy knoll of a central Tennessee rest stop. It's a clear night and they spar under moonlight.

Sin lands a tap in the midst of their delicate dance and it occurs to Cass that while she has a long way to go and her training is almost backwards from Cass' own, Sin has the potential to be better than them all. If she is allowed to be. If Cass fights, tooth and nail, for the world's other great martial artists to _let_ Sin be.

They collapse together onto the grass, the summer dandelions kicking up into the air around them.

Laughter emerges from them both. It's been almost two weeks since Sin mentioned missing home. Though, she misses her "sister."

The stars are glorious tonight and Cass feels so happily _small_ beneath them.

Silence carries between them for a moment longer when Sin shifts to look more toward Cass.

"Since Sister brought me to America…" Sin says, carefully and quietly, "I… I have never been happy. With me. With _knowing_ or with… looking not like Sister. I want to be the little girl Sister was. But Sister has never known. Not like us."

Cass takes a breath. "You're happy?"

"Most of time," Sin mutters as she hugs her knees against her chest. "I should always be happy. But I'm not. I _know._ And I only want to be like Sister… but I'm too unlike her in many ways." The girl's eyes tear. "How can I be a Black Canary… when I'm _me?"_

Frowning, Cass reaches toward her student, takes the girl's hand gently into her own. She squeezes.

"You can be," Cass assures her. "I was… I _am_ Batgirl. And I knew."

Sin fidgets but doesn't dare pull her hand from Cass' hold. She squeezes back instead. "But… how?"

"Carve our own way," Cass answers simply. She smiles at Sin. "We don't bend who we are. You bend too far, you break. We stand tall. Mistakes and all."

She receives no warning when Sin wraps herself around Cass' neck.

* * *

The end of their travels is exactly where they began. A floral shop in Gotham.

They are both anxious to be home, to be with their loved ones, but Cass thinks that Gotham manages to seem even smaller after their travels. Sin seems to be looking upon its buildings and streets with a degree of scrutiny.

Dinah nearly knocks the cycle over when she tackles her daughter with a hug, but Cass is good enough to kick the stand down just before it rocks back.

She watches, with some unknown coolness in the pit of her stomach, as Sin clambers into Dinah's arms and is pulled away. It makes her mouth go dry.

When she feels a broad hand on her shoulder, she does not have to look to see who it is, however. She merely leans into it and rests her head against Bruce's side, smiling as Barbara rolls over and pulls her off the bike and into a hug.

There are so many questions and so many stories that it actually surprises Cass when they're inside the apartment and putting Sin in school is brought up so soon.

"No."

The adults look across the way to Sin. Cass proudly sits straight next to her. The younger girl's eyes are lit with a vicious fury.

Dinah blinks. "Sin, honey," she says slowly, confused, "the school will help you deal with your problems. Curb your abilities."

"I don't need it," Sin says, looking at Dinah with the slightest bit of less respect and worship than she had only moments before. "I won't change a part of who I am."

Cass nods.

The three look at them like they're alien creatures.

"You _have_ to go to school, and this is good for you," Dinah says, still not comprehending.

"No!" Sin snaps. "You don't trust me, but I _can_ be trusted! You want me to forget who I am, but I'm better because I learned more about _me."_

Cass takes Sin's hand and squeezes it. Her eyes never leave the other adults. "This is who we are. And you will _have_ to accept it," she says crisply.


End file.
